The present invention relates to a pneumatic nail gun, and particularly to a pneumatic nail gun having a movable cylinder and slidable sleeve valve.
Pneumatic nail gun generally utilizes a compressed high pressure air to drive a piston to punch a nail, for joining two objects by shooting a nail through both objects. A conventional pneumatic nail gun can be classified into two kinds, one kind being coupled with a magazine, another kind being coupled with a canister. The magazine generally contains the T-shaped or I-shaped nail rows and utilizes an elastic deformation force of a spring to drive each nail to the nail feeding mechanism. The canister contains full-round head strings of larger nails, which is combined with a nail pusher. The nail pusher utilizes a high pressure air and spring to drive each nail to the nail feeding mechanism.
The general structure and function of a nail gun is briefly introduced as follows. A nail gun has a gun body, the gun body having a gun handle and a gun head; a fastening cylinder disposed in the gun head; a high-pressure air pipe coupled to one end of the gun handle, and a high-pressure air being input and introduced into the cylinder; a piston disposed in the cylinder, the piston connected to a nail shooting mechanism at the external end of the gun head, and the nail shooting mechanism coupled to a nail magazine. When the nail gun is triggered, and the piston is pushed outward by the air pressure such that the nail shooting mechanism can shoot out the nail at the nailing position. In addition, an air chamber is provided at an outer peripheral surface, which receives high pressure air from the cylinder to drive the piston to its original position when the piston moves to its lower dead center.
However, the air chamber just can receive the high pressure air when the piston moves downward and be closed when the piston moves upward. That is the air chamber can not receive high pressure air when the piston moves upward. Thus, the collection of the high pressure air in the air chamber for upward movement of the piston is limited, and the stability of the upward movement of the piston is lower. Especially, in the process of continuous nail punching, the instability of upward movement of the piston lowers the speed and efficiency of nail punching.
For resolving the problem, one method of adding the cubage of the air chamber is provided in recently technology. However, the method still is not an ideal resolution.
Accordingly, what is needed is a pneumatic nail gun that can overcome the above-described deficiencies.